This invention relates to extended-release compositions and their methods of use. More particularly to salt-water-soluble extended-release tablet compositions containing a benign acidic agent and the method of using the formulation for controlling the plaque build up in water and waste disposal systems.
The prevention of the build up of calcium salts in water pipes has been addressed for many systems, such as hot water heaters. The solution is often to remove the calcium from the water before it enters into the pipes. At sea, saltwater from the ocean is the process water used for ships. It would be impractical and too expensive to remove all of the calcium from sea water to meet the needs of the ship.
One of the most critical problems on board ship is the build up of calcium salts in the pipes of the ship's collection, holding, and transfer system (CHT system) used for waste disposal. Calcium in the seawater reacts with various components in urine, e.g. uric acid and oxalic acid, to form calcium salts which are insoluble in the water used to flush the pipes. These calcium salts form a plaque on the inside surface of the pipes. After a few months, the pipes become severely blocked by the build up of plaque and the system must be cleaned by hydroblasting. The hydroblasting process takes many days and many man hours to complete, and requires that the system be out of commission for that period of time.
A number of different approaches have been tried to alleviate the plaque build-up problem. The Royal Navy attempts to prevent plaque formation in its ships' CHT systems by removing the calcium from the sea water used; this is accomplished with a water softener, e.g., Calgon.RTM. and/or similar products. This method, however, is extremely expensive. The present method used on United States Naval vessels is to add sulfamic acid to the flush water. Maintaining the proper acidity of the fluid in the pipes slows down or prevents the formation of plaque produced by the precipitation of calcium salts.
Sulfamic acid is a low cost solid, however, its use presents many problems. Sulfamic acid is a strong acid and must be handled with extreme care, e.g., use of protective clothing and masks. Presently, the Navy uses perforated plastic bags containing sulfamic acid in shipboard urinals to control the build up of plaque in pipes. When handling the bags, sulfamic acid dust is spread throughout the air and is deposited on anything that comes in contact with the bags. The bag must be placed in a plastic dispenser which is then placed in the urinal. After the sulfamic acid is leached from the bag by the urinal flush water, the old bag must be retrieved from the dispenser, disposed of, and replaced with a new bag. The use of these bags of sulfamic acid: exposes a person to the harmful sulfamic acid dust which may be inhaled or touched; exposes a person to direct contact with the sulfamic acid; and exposes a person to the unhealthy environment of the urinals. Furthermore, it is difficult to observe when the contents of the bag have been depleted of the sulfamic acid because a significant amount of the volume of the bag is composed of insoluble products. All of these inconveniences result in the bags not being replaced often enough to hinder plaque build up in the CHT system. The use of these sulfamic acid bags in their dispensers has also been shown to be marginally effective at controlling plaque build-up because of the erratic pH levels they produce. By example, over a testing period of four days, the use of the sulfamic acid bags in four urinals produced a pH range of 2.0 to 8.5.
The prior art methods are prohibitively expensive, present safety hazards to users, are cumbersome to employ, are difficult to monitor, have been proven to be ineffective, and generate waste which must be manually disposed of and can be environmentally harmful.
One object of this invention is the provision of a method for preventing and dissolving plaque build up.
A still further object of this invention is the provision of a method for preventing and dissolving plaque build up using an extended-release system.
And yet another object of this invention is the provision of a method for preventing and dissolving plaque build up which is not environmentally harmful.
A still further object of this invention is the provision of a method for preventing and dissolving plaque build up which is safe to the user.
A still further object of this invention is the provision of a method for preventing and dissolving plaque build up which is effective and inexpensive to manufacture.
Yet another object of this invention is the provision of a extended-release composition to be used for preventing and dissolving plaque build up.
It is another object of this invention to provide an extended-release composition which is totally salt-water soluble and leaves no waste product to be manually disposed of.
It is yet another object of this invention to provide an extended-release composition which is easy to dispense and easy to monitor.
It is still another object of this invention to provide an extended-release composition which remains effective over a period of one to three days of normal usage.